The winning ticket of Wednesday's €4.2m Lotto draw was sold in Mohill, Co Leitrim, the National Lottery has confirmed.
The ticket was purchased at Centra on Station Road, which is run by the Baxter family.
Speaking on RTÉ's Morning Ireland, shop owner Gene Baxter said the family and staff were surprised and delighted the ticket was sold at their store.
"There's a lot of speculation this morning [about] who is the lucky winner," he said.
"But we have no clue yet anyway.
"We're quite happy for anyone who did win and we wish them the best of luck.
"We hope maybe a local. Whoever wins it, it's the luck of the draw".
The National Lottery is urging people to check their tickets for Wednesday night's jackpot worth €4,257,050.
Mr Baxter said the family business has sold some winning tickets before but none for an amount of this size.
At this time of year there are a lot of people passing through Mohill, Mr Baxter said, as people holiday in the area.
